1. Field of the Invention:
The invention is directed to a coupling assembly.
2. Description of Related Art:
A known coupling assembly is described in U.S. Pat. No. 3,903,885. In this known coupling assembly, the shaped sealing, made of an elastic rubber material, is cap-shaped and has a conical bottom. The conical bottom is arranged at the rear end of the passage of the coupling assembly, averted from the tip of the housing. The inner diameter of the shaped sealing is considerably larger than the outer diameter of the catheter, which is sealingly guided through a central bore in the conical bottom. The conical bottom is flexible, so that it is drawn rearward and thus is tilted over when the catheter is withdrawn, thereby exerting a stopping effect on the catheter by radially narrowing the bore.
For removing the coupling assembly after successfully positioning the catheter, both halves of the coupling assembly housing can be radially separated after the catheter tip has been drawn out of the hub cone of the sheath. The shaped sealing is slit longitudinally so that after taking apart both halves of the housing of the coupling assembly, the catheter can also be radially removed from the shaped sealing, which is firmly attached to one half of the housing.
By the coupling assembly, a catheter is connected to the hub cone of a sheath (for example, a "Braunule"), which sheath after puncturing, e.g., of a blood vessel, has been inserted thereinto. The end of the coupling assembly averted from the sheath can have a protecting cover applied thereto for protecting the catheter against contamination. The catheter is introduced into the blood vessel through the coupling assembly and the sheath.
According to the state of the art, the interior of the sheath and of the coupling assembly are in communication with the blood circulation of the patient between the time that the coupling assembly is coupled to the hub cone of the sheath until the time that the catheter is advanced into the tip of the sheath. Due to the excess pressure of the blood circulation, blood issues to the outside from the separating slits between both halves of the housing of the coupling assembly. This makes it possible that personnel may be contaminated by the blood of the patient while the catheter is being positioned. In this manner, there are spread contagious diseases being transmitted by blood.
In the known coupling assembly, the issuing of blood out of the separating slits between the two halves of the housing is not prevented, because the shaped sealing is slit longitudinally and because it is arranged at the rear end of the passage. Consequently, during the critical time period, a large part of the length of the passage is filled with blood which can freely exit to the outside in a radial direction. The known shaped sealing is effective too late and, for spatial and functional reasons, does not allow relocation to the front end.
It is an object of the present invention to improve the coupling assembly in such a manner that radial issuing of blood from the separating slits between both halves of the housing is reliably prevented.